Bucher CB, Linden A, Heimgartner H. Synthesis and Solid State Conformation of Tetrapeptide Amides Containing two Aib and two (αMe)Phe Residues - Use of Enantiomerically Pure 2-Benzyl-2-methyl-2H-azirin-3-amines as (αMe)Phe-Synthons.
Chem Biodivers 2020;
17:e2000246. [PMID:
32368841 DOI:
10.1002/cbdv.202000246]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/05/2020] [Indexed: 01/15/2023]
Abstract
A series of tetrapeptide amides containing two aminoisobutyric acids (Aib) and two α-methylphenylalanine ((αMe)Phe) units were prepared through the 'azirine/oxazolone method'. New 2-benzyl-2-methyl-2H-azirin-3-amines have been used for the selective introduction of (S)- and (R)-(αMe)Phe, respectively. The solid-state conformations of five tetrapeptide amides were determined by X-ray crystallography. In all cases, two β-turns stabilize 310 -helical conformations and it was confirmed that, in contrast to proteinogenic amino acids, the configuration of (αMe)Phe does not determine the screw sense of the helix.
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